The Peace Requiem (円満鎮魂曲, Enman Chinkonkyoku) is the ultimate plan of Zoku, somehow involving the use of Datara, the Ten-Tails, in order to end all war and bring the world into an era of "peace". Once this era of peace is instilled, he then plans on using the power of Datara to reduce creation to nothing, thus ending what he calls the "horrific era of humans".
The plan was tested early on when Seireitou Hyūga, unknowingly from Zoku's prodding, unleashed the plan on the world without the involvement of the Ten-Tails. While his plan at first seemed to be succeeding, it did not stop war from plaguing the world, causing it to ultimately fail. After forming the Kagekenin, Zoku himself revived the plan to be carried out with him at its behest.
Zoku's plan consists of many parts. The first stage of the plan is to capture the two remaining tailed beasts; Kurama, the Nine-Tails, and Gyūki, the Eight-Tails. Once done, Ryun Uchiha must be captured and have Datara, the Ten-Tails, which had been partially revived using seven of the tailed beasts and portions of the Kurama and Gyūki, extracted from him. Zoku would then complete the Ten-Tails by re-merging it with Kurama and Gyūki and place it under his control with his mind control abilities.
In the second stage of the Requiem, Zoku would use Datara to beat the shinobi nations and the Lost Lands into submission; essentially making himself the sole leader of the world. He could then disarm the nations and force the world into a false era of peace in which no war exists. With the nations being defenseless, Zoku would be free to move about without having to worry about a war of retaliation.
Once this occurs, the plan's final stage can occur. Using his completed Ten-Tails, Zoku will have the beast reduce creation to nothing using its overwhelming power, thus allowing the world to end, as well as what he calls the "horrific era of humans". Datara would then start the world anew, just as it did centuries before, by becoming the progenitor of the world once again.
Unbeknownst to most of the world, Zoku decided to test the Peace Requiem and did so by planting knowledge of the plan in the man called Seireitou Hyūga. How he did this, however, is unknown.
In his version, Seireitou initiated war with the entire world, bringing most of the nations under his command by holding their Daimyō hostage. During the course of two months, Seireitou went about unifying the world. In the background, however, he prepared his son, Suzaku Hyūga for the role he would play in the plan. With the world's hatred on Seireitou, due to his usurpation of power, he held a celebration to mark the occasion of his ascension to world rulership, and had Suzaku attack him with the hopes of killing him; thus bringing the world into an era of peace and ending all war.
Suzaku, however, botched the assassination attempt, causing Seireitou to survive. Order within Seireitou's new empire soon deteriorated, the countries regained their individuality and war broke out, thus marking the plan a failure. Zoku, however, was able to gain a great deal of data from the attempt, having left large portions of the plan out (such as the tailed beasts' involvement and the use of their power to keep the nations in line) just to see what would happen.
- Zoku claims that Ryun Uchiha and, ironically, Seireitou Hyūga are the biggest reasons why his plan has not yet succeeded.